Haploidentical Hematopoietic Cell Transplantation for Children With Hematologic Malignancies and Myelodysplasia

Inclusion Criteria: * Patient lacks an HLA matched sibling donor. * Meets criteria nonhematopoietic organ function according to NCH BMT SOP09. * If subjects have received a first HCT, they must be eligible for a second HCT if their disease has recurred. * High resolution HLA and KIR typing * The subject cannot have an active untreated infection. Viremia by PCR analysis is not considered an active infection but may require immediate viral prophylaxis. Patients with possible fungal infections must have had at least 2 weeks of appropriate anti- fungal therapy and be asymptomatic. * Negative pregnancy test for females ≥11 years of age or post- menarche. * Sexually active males and females of childbearing potential must agree to use a form of contraception considered effective and medically acceptable by the Investigator. (Non-childbearing potential defined as pre-menarche, greater than one year post-menopausal or surgically sterilized). * Subjects must be ≤30 years at the time of consent. * Signed consent by parent/guardian and assent if appropriate for subjects \< 18 years of age. Signed consent by patient/subject if ≥18 years of age. Exclusion Criteria: * Patient does not have a suitable donor who is willing and able (meets donor criteria). * Patient has donor-specific anti-HLA antibodies at the time of enrollment * Patient reports a history of allergic reactions to murine protein Donor Eligibility: * The donor must be ≥18 years of age at the time of the informed consent conference. * The donor must be a related donor * The donor will be evaluated according to the current NCH BMT SOP 04 and must meet all criteria. * The donor must be able and willing to undergo G-CSF mobilization and stem cell apheresis. * The patient does not have donor specific anti-HLA antibodies